1. Field of the Invention
The present invention pertains to a luggage type container, usually a manually transported suitcase, that is equipped with wheels or rollers to enable the user to transport the suitcase by pushing or pulling it rather than lifting and carrying it.
2. Description of Prior Art
Suitcases with built in wheels or ball bearings that allow them to be transported by being towed along a floor rather than being carried have become popular in recent years as more people carry their own luggage.
One earlier type of suitcase uses four casters mounted on the perimeter of the base of the suitcase which is towed with a strap. The disadvantage of this system is that the suitcase tends to wander or "fishtail" so it is difficult to control. As a result, this system is currently not very popular.
Most suitcases are built in the general shape of a right rectangular parallelepiped, or prism, having three unequal dimensions. One type of suitcase that has become increasingly popular is one that has two wheels mounted on a rigid axle or axles located along an edge where the base and one side of the suitcase intersect. The user tilts the opposite end, which is the top of the suitcase, so that only the two wheels remain on the floor, then pulls and steers the suitcase by means of a rigid handle extending from one of the top edges. Except for the wheels, the suitcase is held off the ground by the user keeping the rigid handle partially elevated. The axles are perpendicular to the direction of travel so that while the wheels are rolling, they remain fixedly oriented with respect to the suitcase.
A frequent configuration for this type of suitcase is to have the height be the longest dimension. Some manufacturers refer to this type of case as "upright suitcase" to distinguish it from the traditional, hand carried, suitcase which usually had its longest dimension horizontal. When, stationary in the upright position, the base of this type of suitcase, which includes the set of wheels and any small support legs, rests on the ground, and the handle extends from the top. Thus the base is in the shape of a rectangle. The longer edges of the base have the intermediate dimension of the prism and the shorter edges of the base have the shortest dimension. If the suitcase is built with the wheels located along a longer edge, the wheelbase can be made wider. When being transported in this manner, the center of gravity of the suitcase will be lower, and the suitcase will be more stable and easier to manage.
The disadvantage of mounting the wheels along this longer edge is that the towed suitcase can be too wide to fit through such things as narrow doorways or the aisles of commercial airliners. Currently, many passengers lift and carry their wheeled luggage down the narrow aisle of an aircraft. In order to do so, they must hold the suitcase awkwardly either in front or behind them.
The disadvantage of building the suitcase with the wheels located along a shorter edge is that while the suitcase will fit through narrow restrictions it will tip easily when going over bumps or traversing sloped surfaces in open areas.